TUNIS (Reuters) - U.N. Secretary General Antonio Guterres voiced concern at developments in Libya’s oil crescent on Wednesday, calling for de-escalation and the return of oil resources to recognised authorities, his spokesman said in a statement.

“The Secretary-General recalls, as stipulated in Security Council resolution 2259 (2015), the need for unity of Libyan institutions and the exclusive right of the National Oil Corporation to export the country’s oil,” the statement said.

“He calls for de-escalation and for the return of all natural resources, their production and their revenues to the control of the recognised Libyan authorities.”

Earlier in the day, the United States, France, Britain and Italy said they were deeply concerned by an announcement that east Libyan oil fields and ports would be handed over to a parallel National Oil Corporation (NOC) based in Libya’s east.

Guterres reiterated his support for his envoy to Libya, Ghassan Salame, who is spearheading international efforts to stabilise and reunify the North African country after years of turmoil following a 2011 uprising.

“The United Nations stands ready to work with the Libyan people, the legitimate Libyan institutions and all stakeholders to achieve a fair and equitable distribution of the country’s natural wealth as part of a peaceful, stable and prosperous Libya,” the U.N. statement said.